Re: [PATCH 2/7] clk: qcom: ipq8074: disable USB GDSC-s SW_COLLAPSE

Bjorn Andersson
2022-05-06T03:33:39Z

On Mon 25 Apr 13:22 CDT 2022, Robert Marko wrote:

> Like in IPQ6018 Qualcomm intentionally disables the SW_COLLAPSE on the USB
> GDSC-s in the downstream 5.4 kernel.
>
> This could potentially be better handled by utilizing the GDSC driver, but
> I am not familiar with it nor do I have datasheets.

Could you please give it a try before we pick this up?
Look at e.g. drivers/clk/qcom/gcc-sdm845.c how usb30_prim_gdsc and
usb30_sec_gdsc are defined, the offsets in specified in .gdscr should be
the same offsets you give below.

Then you specify an array of struct gdsc *, associating the two gdscs
you have specified to some identifier (USB30_PRIM_GDSC and
USB30_SEC_GDSC is used in sdm845) and reference this list as .gdscs and
num_gdscs in the gcc_ipq8074_desc.

The last part is to tie the USB controllers to the two GDSCs, this is
done by simply specifying:

power-domains = <&gcc USB30_PRIM_GDSC>;

and USB30_SEC_GDSC, in the two USB nodes in DeviceTree. SW_COLLAPSE will
be toggled by the PM state of the USB driver, like it's done on e.g.
sdm845.

Regards,
Bjorn

>
> Signed-off-by: Robert Marko <robimarko@gmail.com>
> ---
> drivers/clk/qcom/gcc-ipq8074.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/drivers/clk/qcom/gcc-ipq8074.c b/drivers/clk/qcom/gcc-ipq8074.c
> index 2ebd1462db78..65249a03a672 100644
> --- a/drivers/clk/qcom/gcc-ipq8074.c
> +++ b/drivers/clk/qcom/gcc-ipq8074.c
> @@ -4806,6 +4806,11 @@ static int gcc_ipq8074_probe(struct platform_device *pdev)
> if (IS_ERR(regmap))
> return PTR_ERR(regmap);
>
> + /* Disable SW_COLLAPSE for USB0 GDSCR */
> + regmap_update_bits(regmap, 0x3e078, BIT(0), 0x0);
> + /* Disable SW_COLLAPSE for USB1 GDSCR */
> + regmap_update_bits(regmap, 0x3f078, BIT(0), 0x0);
> +
> clk_alpha_pll_configure(&ubi32_pll_main, regmap, &ubi32_pll_config);
> clk_alpha_pll_configure(&nss_crypto_pll_main, regmap,
> &nss_crypto_pll_config);
> --
> 2.35.1
>